Medical device

ABSTRACT

Provided is a medical device comprising an inner tubular member, an outer tubular member having a distal end and an open window disposed at the distal end, a first electrode and/or a second electrode disposed at the distal end of the outer tubular member, and a cannulated plunger or armature or shaft configured to drive the inner tubular member to cut tissue in cooperation with the open window of the outer tubular member wherein the first electrode and the second electrode are configured to provide RF energy needed for surgical operation and wherein the first and the second electrodes may be configured to be symmetrical or substantially symmetrical along a longitudinal axis of the outer tubular member or wherein the first electrode is configured to cover the open window of the outer tubular member and extended to one side of the outer tubular member and the second electrode is configured to be disposed on the other side of the outer tubular member. Also provided are methods of making a medical device as described herein.

FIELD

The present disclosure relates generally to a medical device. Moreparticularly, the disclosure relates to a microdebrider or shaverconfigured to be capable of resecting and coagulating tissue in nasalrelated surgical operations.

BACKGROUND

Surgical apparatus used to shave, cut, resect, abrade and/or removetissue, bone and/or other bodily materials are known. Such surgicalapparatus can include a cutting surface, such as a rotating orreciprocating blade disposed on an elongated inner tube that is rotatedwithin an elongated outer tube having a cutting window. The inner andouter tubes together form a surgical cutting instrument or unit.Microdebrider shaver blades are common instruments used in endoscopicsurgery. The shaver blade delivers high speed mechanical cutting oftissue at a specified area of anatomy that the surgeon can reach througha minimally invasive incision or natural orifice. One challenge duringprocedures using such instruments can be the slowing down or stopping ofbleeding (hemostasis) during the procedure. One solution for maintainingproper hemostasis during a procedure is to utilize an electrocauteryinstrument that can be used inside the same minimally invasive surgicalcorridor. In a minimally invasive procedure, every time the surgeonexchanges the cutting instrument for the electrocautery instrument thereis a corresponding increase in the time required to perform theprocedure and there is a risk of traumatizing the anatomy due to theexchange of the instruments. Thus, it is convenient to combine themechanical cutting and electrocautery instruments to form one instrumentperforming both functions. By providing a microdebrider shaver bladethat also can perform electrocautery, the need to perform tool exchangesat the surgical site is reduced and can even be eliminated.

SUMMARY

In one aspect, the present disclosure provides a medical device. In anembodiment, the medical device comprises a first electrode. In anembodiment, the medical device comprises a first electrode and a secondelectrode. In an embodiment, the medical device comprises a tubularmember. In an embodiment, the medical device comprises an inner tubularmember and an outer tubular member. In an embodiment, the medical devicecomprises a cannulated shaft. In an embodiment, the medical devicecomprises a cannulated plunger. In an embodiment, the medical devicecomprises a cannulated armature. In an embodiment, the medical devicecomprises a handpiece or handle.

In one aspect, the present disclosure provides a medical devicecomprising a tubular member and a first electrode. In an embodiment, thetubular member is configured to have a proximal end and a distal endwith the first electrode disposed at the distal end of the tubularmember. In an embodiment, the tubular member is configured to have anopen window disposed at the distal end. In an embodiment, the firstelectrode is configured to encompass the open window of the tubularmember. In an embodiment, the open window is configured to besymmetrical or substantially symmetrical along a longitudinal axis ofthe tubular member. In an embodiment, the first electrode is configuredto be symmetrical or substantially symmetrical along a longitudinal axisof the tubular member. In an embodiment, the first electrode isconfigured to encompass the open window of the tubular member andconfigured to be symmetrical or substantially symmetrical along alongitudinal axis of the tubular member. In an embodiment, the medicaldevice also comprises a second electrode. In an embodiment, the secondelectrode is disposed at the distal end of the tubular member. In anembodiment, the second electrode is configured to be symmetrical orsubstantially symmetrical along a longitudinal axis of the tubularmember. In an embodiment, both the first electrode and the secondelectrode are configured to be symmetrical or substantially symmetricalalong a longitudinal axis of the tubular member. In an embodiment, thefirst electrode is configured to cover the open window area of thetubular member with extension to one side of the distal end of thetubular member and the second electrode configured to be disposed on theopposite side of the distal area of the tubular member when the first orthe second electrode is not symmetrical along a longitudinal axis of theouter tubular member.

In one aspect embodiment, the present disclosure provides a medicaldevice comprising an outer tubular member, an inner tubular member, anda first electrode. In an embodiment, the outer tubular member isconfigured to have a proximal end and a distal end with the firstelectrode disposed at the distal end of the outer tubular member. In anembodiment, the outer tubular member is configured to have an openwindow disposed at the distal end of the outer tubular member. In anembodiment, the first electrode is configured to cover the open windowof the outer tubular member. In an embodiment, the open window isconfigured to be symmetrical or substantially symmetrical along alongitudinal axis of the outer tubular member. In an embodiment, thefirst electrode is configured to be symmetrical or substantiallysymmetrical along a longitudinal axis of the outer tubular member. In anembodiment, the inner tubular member is configured to have an opendistal end. In an embodiment, the inner tubular member is configured tobe received within the outer tubular member. In an embodiment, the openwindow of the outer tubular member and the open distal end of the innertubular member are configured to form a cutting tool once the medicaldevice is in operation. In an embodiment, the medical device alsocomprises a second electrode. In an embodiment, the second electrode isdisposed at the distal end of the outer tubular member. In anembodiment, the second electrode is configured to be symmetrical orsubstantially symmetrical along a longitudinal axis of the outer tubularmember. In an embodiment, both the first electrode and the secondelectrode are configured to be symmetrical or substantially symmetricalalong a longitudinal axis of the outer tubular member. In an embodiment,the first electrode is configured to cover the open window area of theouter tubular member with extension to one side of the distal end of theouter tubular member and the second electrode configured to cover theopposite side of the distal area of the outer tubular member when thefirst or the second electrode is not symmetrical along a longitudinalaxis of the outer tubular member.

In one aspect, the present disclosure provides a medical devicecomprising an outer tubular member, an inner tubular member, acannulated plunger, and a first electrode. In an embodiment, the outertubular member is configured to have a proximal end and a distal endwith the first electrode disposed at the distal end of the outer tubularmember. In an embodiment, the outer tubular member is configured to havean open window disposed at the distal end of the outer tubular member.In an embodiment, the first electrode is configured to cover the openwindow of the outer tubular member. In an embodiment, the open window isconfigured to be symmetrical or substantially symmetrical along alongitudinal axis of the outer tubular member. In an embodiment, thefirst electrode is configured to be symmetrical or substantiallysymmetrical along a longitudinal axis of the outer tubular member. In anembodiment, the inner tubular member is configured to have an opendistal end. In an embodiment, the inner tubular member is configured tobe received within the outer tubular member. In an embodiment, the openwindow of the outer tubular member and the open distal end of the innertubular member are configured to form a cutting tool once the medicaldevice is in operation. In an embodiment, the cannulated plunger isconfigured to drive the inner tubular member. In an embodiment, thecannulated plunger is configured to reciprocate the inner tubularmember. In an embodiment, the cannulated plunger is configured to beused as a suction line. In an embodiment, the cannulated plunger isconfigured to drive a working member and to function as a suction lineas well. In an embodiment, the inner tubular member and the outertubular member are configured to be a working member. In an embodiment,the medical device also comprises a second electrode. In an embodiment,the second electrode is disposed at the distal end of the outer tubularmember. In an embodiment, the second electrode is configured to besymmetrical or substantially symmetrical along a longitudinal axis ofthe outer tubular member. In an embodiment, both the first electrode andthe second electrode are configured to be symmetrical or substantiallysymmetrical along a longitudinal axis of the outer tubular member. In anembodiment, the first electrode is configured to cover the open windowarea of the outer tubular member with extension to one side of thedistal end of the outer tubular member and the second electrodeconfigured to cover the opposite side of the distal area of the outertubular member when the first or the second electrode is not symmetricalalong a longitudinal axis of the outer tubular member.

In one aspect, the present disclosure provides a medical devicecomprising an outer tubular member, an inner tubular member, acannulated armature and a first electrode. In an embodiment, the outertubular member is configured to have a proximal end and a distal endwith the first electrode disposed at the distal end of the outer tubularmember. In an embodiment, the outer tubular member is configured to havean open window disposed at the distal end of the outer tubular member.In an embodiment, the first electrode is configured to cover around theopen window of the outer tubular member. In an embodiment, the openwindow is configured to be symmetrical or substantially symmetricalalong a longitudinal axis of the outer tubular member. In an embodiment,the first electrode is configured to be symmetrical or substantiallysymmetrical along a longitudinal axis of the outer tubular member. In anembodiment, the inner tubular member is configured to have a distal endand an open window disposed at the distal end. In an embodiment, theinner tubular member is configured to be received within the outertubular member. In an embodiment, the open window of the outer tubularmember and the open window of the inner tubular member are configured toform a cutting tool when the medical device is in operation. In anembodiment, the cannulated armature is configured to drive the innertubular member. In an embodiment, the cannulated armature is configuredto oscillate or rotate the inner tubular member. In an embodiment, thecannulated armature is configured to be used as a suction line. In anembodiment, the cannulated armature is configured to drive a workingmember and to function as a suction line as well. In an embodiment, theinner tubular member and the outer tubular member are configured to be aworking member. In an embodiment, the medical device also comprises asecond electrode. In an embodiment, the second electrode is disposed atthe distal end of the outer tubular member. In an embodiment, the secondelectrode is configured to be symmetrical or substantially symmetricalalong a longitudinal axis of the outer tubular member. In an embodiment,both the first electrode and the second electrode are configured to besymmetrical or substantially symmetrical along a longitudinal axis ofthe outer tubular member. In an embodiment, the first electrode isconfigured to cover the open window area of the outer tubular memberwith extension to one side of the distal end of the outer tubular memberand the second electrode configured to cover the opposite side of thedistal area of the outer tubular member when the first or the secondelectrode is not symmetrical along a longitudinal axis of the outertubular member.

In one aspect, the present disclosure provides a medical devicecomprising an inner tubular member, an outer tubular member, a motorassembly, a first electrode, and a handpiece. In an embodiment, theouter tubular member is configured to have a proximal end and a distalend with a first electrode disposed at the distal end of the outertubular member. In an embodiment, the outer tubular member is configuredto have an open window disposed at the distal end of the outer tubularmember. In an embodiment, the first electrode is configured to cover theopen window of the outer tubular member. In an embodiment, the openwindow is configured to be symmetrical or substantially symmetricalalong a longitudinal axis of the outer tubular member. In an embodiment,the first electrode is configured to be symmetrical or substantiallysymmetrical along a longitudinal axis of the outer tubular member. In anembodiment, the inner tubular member is configured to have a distal endand an open window disposed at the distal end. In an embodiment, theinner tubular member is configured to be received within the outertubular member. In an embodiment, the open window of the outer tubularmember and the open window of the inner tubular member are configured toform a cutting tool when the medical device is in operation. In anembodiment, the motor assembly is configured to drive the inner tubularmember. In an embodiment, the inner tubular member is configured to beconnectable to a suction line. In an embodiment, both the inner tubularmember and the outer tubular member are configured to be detachable fromthe handpiece. In an embodiment, both the inner tubular member and theouter tubular member are configured to be fixedly attached to thehandpiece. In an embodiment, the medical device also comprises a secondelectrode. In an embodiment, the second electrode is disposed at thedistal end of the outer tubular member. In an embodiment, the secondelectrode is configured to be symmetrical or substantially symmetricalalong a longitudinal axis of the outer tubular member. In an embodiment,both the first electrode and the second electrode are configured to besymmetrical or substantially symmetrical along a longitudinal axis ofthe outer tubular member. In an embodiment, the first electrode isconfigured to cover the open window area of the outer tubular memberwith extension to one side of the distal end of the outer tubular memberand the second electrode configured to cover the opposite side of thedistal area of the outer tubular member when the first or the secondelectrode is not symmetrical along a longitudinal axis of the outertubular member.

In one aspect, the present disclosure provides a medical devicecomprising: an inner tubular member, an outer tubular member, acannulated armature, a first electrode, a second electrode and ahandpiece. In an embodiment, the inner tubular member is configured tohave an open window at its distal end. In an embodiment, the innertubular member is configured to be operably connected to the cannulatedarmature. In an embodiment, the outer tubular member is configured tohave a distal end and an open window disposed at the distal end. In anembodiment, the open window of the inner tubular member and the openwindow of the outer tubular member are configured to form a cutting toolwhen the medical device is in operation. In an embodiment, the firstelectrode is configured to be disposed at the distal end of the outertubular member. In an embodiment, the inner tubular member is configuredto be received within the outer tubular member. In an embodiment, thefirst electrode is configured to wrap around the open window of theouter tubular member. In an embodiment, the open window of the outertubular member is configured to be symmetrical or substantiallysymmetrical along the longitudinal axis of the outer tubular member. Inan embodiment, the first electrode is configured to be symmetrical orsubstantially symmetrical along the longitudinal axis of the outertubular member. In an embodiment, the cannulated armature is configuredto be used as a suction line. In an embodiment, the cannulated armatureis configured to drive a working member and to function as a suctionline as well. In an embodiment, the inner tubular member and the outertubular member are configured to be a working member. In an embodiment,both the inner tubular member and the outer tubular member areconfigured to be detachable from the housing. In an embodiment, both theinner tubular member and the outer tubular member are configured to befixedly attached to the handpiece. In an embodiment, the medical devicealso comprises a second electrode. In an embodiment, the secondelectrode is disposed at the distal end of the outer tubular member. Inan embodiment, the second electrode is configured to be symmetrical orsubstantially symmetrical along a longitudinal axis of the outer tubularmember. In an embodiment, both the first electrode and the secondelectrode are configured to be symmetrical substantially symmetricalalong a longitudinal axis of the outer tubular member. In an embodiment,the first electrode is configured to cover the open window area of theouter tubular member with extension to one side of the distal end of theouter tubular member and the second electrode configured to cover theopposite side of the distal area of the outer tubular member when thefirst or the second electrode is not symmetrical along a longitudinalaxis of the outer tubular member.

In another aspect, the present disclosure provides a method of making amedical device as described herein. In an embodiment, the methodincludes making a medical device with a first electrode disposed at thedistal end of the tubular member as described herein. In an embodiment,the present disclosure also provides a method of making a medical devicewith a first electrode and a second electrode disposed at the distal endof the tubular member as described herein. In an embodiment, the methodincludes making a medical device as described herein by using amicrofabrication process. In an embodiment, the method includes making amedical device as described herein by employing a flexible circuitprocess. In an embodiment, the method includes making a medical deviceas described herein by employing a conductive ink process.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partial sectional view of a medical device in accordancewith one aspect of the present disclosure;

FIG. 2A, FIG. 2B, FIG. 2C, and FIG. 2D are partial schematic views ofthe various features of the working tip section of the medical device ofFIG. 1 .

FIG. 3 is a partial sectional view of a medical device in accordancewith another aspect of the present disclosure;

FIG. 4A and FIG. 4B. are partial schematic views of the various featuresof the working tip section of the medical device of FIG. 3 ;

FIG. 5A, FIG. 5B, and FIG. 5C are, respectively, top, side and bottomschematic views of the outer tubular member incorporating some of thesymmetrical electrode features of the present disclosure;

FIG. 6A, FIG. 6B, and FIG. 6C are corresponding expanded views of thetip portions of FIG. 5A, FIG. 5B, and FIG. 5C, respectively;

FIG. 7A, FIG. 7B, and FIG. 7C are, respectively, top, side and bottomschematic views of the outer tubular member incorporating some of theelectrode design features of the present disclosure;

FIG. 8A, and FIG. 8B are the corresponding expanded views of the tipportion of FIG. 7C.

DETAILED DESCRIPTION

FIG. 1 is a partial sectional view of a medical device in accordancewith one exemplary embodiment of the present disclosure. The medicaldevice 100 of FIG. 1 generally includes a working tip section 10, atubular section 40, a nosecone 50, a housing 60, a handle grip 70(optional), a cannulated plunger 80, and a suction connector 90.

In the above exemplary embodiment, the tubular section 40 may beconfigured to comprise an outer tubular member 20 (not shown in FIG. 1 )and an inner tubular member 30 (not shown in FIG. 1 ). The outer tubularmember 20 may be mounted to the housing 60 through the nosecone 50 andacts as a static member, wherein the inner tubular member 30 is receivedinside the outer tubular member 20, and is configured to be axiallymovable within the outer tubular member 20. It should be understood thatthe outer tubular member 20 may be rotatably, detachably or fixedlymounted to the housing 60. The inner tubular member 30 may be configuredto be connected to the cannulated plunger 80. The cannulated plunger 80is configured to be connectable to a suction source through theconnector 90. In the above embodiments, the inner diameter of the outertubular member 20 may be configured to be slightly larger than the outerdiameter of the inner tubular member 30 (for example, by approximately0.002 inches). This allows the inner tubular member 30 to move freely tohelp minimizing wobbling of the inner tubular member 30 to keep the opendistal end of the inner tubular member closely aligned with the openwindow of the outer tubular member.

In the above exemplary embodiment, the tubular section 40 may beconfigured as one piece, and detachable/attachable from/to the housing60. The tubular section 40 may be made disposable or reusable. Thenosecone 50 may be configured to rotate the tubular section 40 inaddition to being as a coupler between the tubular section 40 and thehousing 60. In particular, the nosecone 50 may be configured to becapable of rotating the outer tubular member to a certain desirableposition to align the outer tubular member with the inner tubularmember. The nosecone 50 may be made disposable or reusable. Thecannulated plunger 80 may be powered by means known in the art such assolenoids connected to a power source. The housing 60 may be madedisposable or reusable. The hand grip 70 may be configured to beoptional, rendering the handpiece to be a linear type. The medicaldevice 100 itself may be made disposable or reusable, and preferablydisposable.

Further information about this type of medical device usingreciprocating mode for cutting may also be found in a U.S. applicationSer. No. 15/880,998 filed on Jan. 26, 2018, the contents of which areincorporated herein in its entirety by reference.

FIG. 2A, FIG. 2B, FIG. 2C, and FIG. 2D illustrate some exemplaryembodiments of a working tip section 10 of a medical device 100 inaccordance with some aspects of the present disclosure. Moreparticularly, FIG. 2A and FIG. 2B show exemplary embodiments of aworking tip section with an outer tubular member 20 having a symmetricalor substantially symmetrical open window and symmetrical orsubstantially symmetrical electrodes disposed at the distal end whilethe inner tubular member has different distal configurations. For bothFIG. 2A and FIG. 2B, the outer tubular member 20 has an open window 21disposed at the distal end of the outer tubular member 20. The openwindow 21 has a surface area 22. The surface area 22 may be preferablyconfigured to have a sharp edge, in particular towards the distal mostend. The open window 21 is configured to be symmetrical or substantiallysymmetrical along a longitudinal axis Z. Even though the open window 21is shown to be disposed at the distal most end, it may also be disposedat a location with some distance away from the farthest end. A firstelectrode is disposed at the distal end of the outer tubular member 20.It is configured to cover the surface area 22 and its neighboring region23 of the outer tubular member 20. It may also be stated as that thefirst electrode is configured to encircle, enclose, surround, envelop,hem in, or wrap around the open window 21 or its neighboring region 23.It is also contemplated that the first electrode may only cover thesurface area 22 of the open window 21 without extending to itssurrounding area 23. The first electrode is configured to be symmetricalor substantially symmetrical along the longitudinal axis Z. The tipsection of FIG. 2A or FIG. 2B is also configured to have an insulatingzone 24. The insulation zone 24 may also be configured to be symmetricalor substantially symmetrical along the longitudinal axis Z. Theinsulation zone 24 may be configured to surround the first electrodewith a constant gap to the first electrode all around. A secondelectrode 25 is disposed on a dielectric layer and configured tosurround the insulation zone 24. The second electrode 25 is configuredto have a runner 25 a which is preferably configured to be parallel tothe longitudinal axis Z. The second electrode 25 is configured to besymmetrical or substantially symmetrical along the longitudinal axis Z.The runner 25 a may be preferably configured to equally or substantiallyequally bisect the open window 21 even though other configurations mayalso be contemplated. The runner 25 a is configured to be connectable toa metallic wire. The second electrode 25 is preferably configured tosurround the insulation zone 24 and maintain aconstant gap with theinsulation zone 24 all around to achieve a more desirable function. Thefirst electrode and the second electrode are configured to form abipolar RF device for cutting and/or coagulating purpose. The outertubular member 20 may be made of metallic or polymeric materials. When ametallic material such as stainless steel is used, the first electrodemay be formed around the open window and its neighboring area of theouter tubular member by putting an insulation layer around the outertubular member. The second electrode may then be formed by puttingconductive materials such as silver, gold, and solder on the insulationlayer even though gold may be preferred as conductive material. Theouter tubular member may be made rigid, malleable, or flexible dependingon the needs and functions of the medical device. Yet, the outer tubularmember may be preferred to be rigid.

FIG. 2A and FIG. 2B also demonstrate different embodiments of the innertubular member of the working tip 10 of a medical device 100. FIG. 2Aillustrates an inner tubular member 30 with a circular open end 31. Thecircular open end 31 is configured to have a sharp edge. This sharp edgeis intended to form a cutting tool with the open window 21 of the outertubular member 20 once the inner tubular member 30 is reciprocated by amechanism such as a plunger and solenoid combination during a surgicaloperation. It may be more preferable to have a sharper surface area atthe distal most end of the open window 21 of the outer tubular member inorder to have a better cutting effect with the open end 31. FIG. 2Billustrates an inner tubular member 30′ with a beveled open end 31′. Thebeveled open end 31′ is configured to have a sharp edge. This sharp edgeis intended to form a cutting tool with the open window 21 of the outertubular member 20 once the inner tubular member 30′ is reciprocated by amechanism such as a plunger and solenoid combination during a surgicaloperation. It is contemplated that the outer tubular member 20 or theinner tubular member 30′ may be rotated/adjusted, for example, through anosecone 50, to align the open window 21 with the beveled distal end 31′to achieve more desirable cutting effect since it may become necessarydue to the beveled nature of the inner tubular member 30′. The innertubular member 30 or 30′ may be made of stainless steel or othermetallic or strong materials so long as it can perform efficientcutting. The inner tubular member may be made rigid, malleable, orflexible depending on the needs and functions of the medical device.Yet, the inner tubular member may be preferred to be rigid.

FIG. 2C and FIG. 2D demonstrate further embodiments of a working tipsection with an outer tubular member 20′ having a symmetrical openwindow with an asymmetrical electrode assembly while the inner tubularmember has different distal configurations. More particularly, FIG. 2Cand FIG. 2D both have an outer tubular member 20′ with an open window21′ disposed at the distal end of the open window 21′. The open window21′ is configured to have a surface area 22′. The surface area 22′ maybe preferably configured to have a sharp edge, in particular towards thedistal most end. The open window 21′ may be preferably configured to besymmetrical or substantially symmetrical along a longitudinal axis Zeven though other geometry or configurations are also contemplated. Eventhough the open window 21′ is shown to be disposed at the distal mostend, it may be disposed at a location with some distance away from thefarthest end. A first electrode is configured to cover the surface area22′ and the shaded area 23′ at the distal end of the outer tubularmember 20′. The shaded area 23′ is disposed on one side of the outertubular member 20′. Consequently, the first electrode is configured tocover the surface area 22′ and extend from the surface area 22′ to oneside of the outer tubularmember 20′. A second electrode 25′ is disposedon a dielectric layer on the other side of the outer tubular member 20′.An insulation zone 24′ is disposed between the first electrode 23′ andthe second electrode 25′. The second electrode 25′ is configured to havea runner 25′a configured to be connectable to a metallic wire. The firstelectrode 23′ and the second electrode 25′ are configured to form abipolar RF device for cutting and/or coagulating purpose. The outertubular member 20′ may be made of metallic or polymeric materials. Whena metallic material such as stainless steel is used, the first electrodemay be formed around the open window and its neighboring area of theouter tubular member by putting an insulation layer around the distalend of the outer tubular member in a manner as insulation zone 24′. Thesecond electrode may then be formed on the other side of the distal endof the outer tubular member. It may also be formed by putting conductivematerials such as silver, gold, and solder on the extended insulationlayer even though gold may be preferred as conductive material. Theouter tubular member may be made rigid, malleable, or flexible dependingon the needs and functions of the medical device. Yet, the outer tubularmember may be preferred to be rigid.

FIG. 2C and FIG. 2D also show different embodiments of the inner tubularmember of the working tip 10 of a medical device 100. FIG. 2Cillustrates an inner tubular member 30 with a circular open end 31. Thecircular open end 31 is configured to have a sharp edge. This sharp edgeis intended to form a cutting tool with the open window 21′ of the outertubular member 20′ once the inner tubular member 30 is reciprocated by amechanism such as a plunger and solenoid combination during a surgicaloperation. It may be more preferable to have a sharper surface areaatthe distal most end of the open window 21′ of the outer tubular memberin order to have a better cutting effect with the open end 31. FIG. 2Dillustrates an inner tubular member with a beveled open end 31′. Thebeveled open end 31′ is configured to have a sharp edge. This sharp edgeis intended to form a cutting tool with the open window 21′ of the outertubular member 20′ once the inner tubular member 30′ is reciprocated bya mechanism such as a plunger and solenoid combination during a surgicaloperation. It is contemplated that the outer tubular member 20′ and/orthe inner tubular member 31′ may be rotated/adjusted, for example,through a nosecone 50, to align the open window 21′ with the beveleddistal end 31′ to achieve more desirable cutting effect since it maybecome necessary due to the beveled nature of the inner tubular memberThe inner tubular member 30 or 30′ may be made of stainless steel orother metallic or strong materials so long as it can perform efficientcutting. The inner tubular member may be made rigid, malleable, orflexible depending on the needs and functions of the medical device.Yet, the inner tubular member may be preferred to be rigid.

FIG. 3 is a partial sectional view of a medical device in accordancewith another exemplary embodiment of the present disclosure. The medicaldevice 1100 of FIG. 3 generally includes a working tip portion 110, atubular section 140, a nosecone 150, a housing 160, a handle grip 170(optional), a cannulated shaft 180, a gear set 181, a motor set 182, anda power connector 183, and a suction connector 190.

In the above exemplary embodiment, the tubular section 140 may beconfigured to comprise an outer tubular member 120 (not shown in FIG. 3) and an inner tubular member 130 (not shown in FIG. 3 ). The outertubular member 120 may be mounted to the housing 160 through thenosecone 150 and acts as a static member, wherein the inner tubularmember 130 is received inside the outer tubular member 120, and isconfigured to be rotatable and/or translational within theouter tubularmember 120. It should be understood that the outer tubular member 120may be rotatably, detachably or fixedly mounted to the housing 160. Theinner tubular member 130 may be configured to be connected to thecannulated shaft 180. The cannulated shaft 180 is rotated or oscillatedand/or translated by the motor set 182 through a gear set 181. The motorset 182 is configured to be powered by a power source through the powerconnector 183.

In the above exemplary embodiment, the tubular section 140 may beconfigured as one piece, and detachable/attachable from/to the housing160. The tubular section 140 may be made disposable or reusable. Thenosecone 150 may be configured to rotate the tubular section 140 inaddition to being as a coupler between the tubular section 140 and thehousing 160. In particular, the nosecone 150 may be configured to becapable of rotating the outer tubular member to a certain desirableposition to align the outer tubular member with the inner tubularmember. The hand grip 170 may be configured to be optional, renderingthe handpiece to be a linear type. The housing 160 may be madedisposable or reusable. The medical device 1100 itself may be madedisposable or reusable, and preferably disposable.

FIG. 4A, and FIG. 4B illustrates some embodiments of a working tipsection 110 of a medical device 1100 of FIG. 3 . More particularly, FIG.4A illustrates a working tip having an outer tubular member 120 asidentically or similarly described with respect to the outer tubularmember 20 of FIG. 2A or FIG. 2B. Consequently, all the features that theouter tubular member 20 has should be equally applicable to the outertubular member 120. Even though FIG. 4A only shows an inner tubularmember 130 (not numbered in FIG. 4A or FIG. 4B) having a distal openwindow 135 with toothed edges, it should be understood that other typesof window shapes and/or configurations are also contemplated. The innertubular member 130 is configured to be rotatable and/or capable oftranslation within the outer tubular member 120. FIG. 4B illustrates aworking tip having an outer tubular member 120′ as identically orsimilarly described with respect to the outer tubular member 20′ of FIG.2C or FIG. 2D. Consequently, all the features that the outer tubularmember 20′ has should be equally applicable to the outer tubular member120′. Even though FIG. 4B only shows an inner tubular member 130 havinga distal open window 135 with toothed edges, it should be understoodthat other types of window shapes and/or configurations are alsocontemplated. The inner tubular member 130 is configured to be rotatableand/or capable of translation within the outer tubular member 120′. Theinner tubular member 130 may be made of stainless steel or othermetallic or strong materials so long as it can perform efficientcutting. The inner tubular member may be made rigid, malleable, orflexible depending on the needs and functions of the medical device.Yet, the inner tubular member may be preferred to be rigid.

FIG. 5A, FIG. 5B, FIG. 5C, FIG. 6A, FIG. 6B, and FIG. 6C are furtherdetailed illustrations of an outer tubular member 20 or 120 asidentically or similarly described with respect to FIG. 2A, FIG. 2B, andFIG. 4A. More particularly, FIG. 5A is a top view of an outer tubularmember 20 or 120. FIG. 5B is a side view of an outer tubular member 20or 120. FIG. 5C is a bottom view of an outer tubular member 20 or 120.FIG. 6A is an expanded top view of the tip portion A of the outertubular member 20 or 120 of FIG. 5A. FIG. 6B is an expanded side view ofthe tip portion B of the outer tubular member 20 or 120 of FIG. 5B. Theleft drawing of FIG. 6C is an expanded bottom view of the tip portion Cof the outer tubular member 20 or 120 of FIG. 5C, and the right drawingof FIG. 6C is an expanded end view of the tip portion C of the outertubular member 20 or 120 of FIG. 5C. FIG. 6A, FIG. 6B, and FIG. 6C showsome preferable relative ratios of first electrode 23 or 123, insulatingzone 24 or 124, and the second electrode 25 or 125 even though otherratios are also contemplated, for example, a ratio of 0.026 to 0.030 to0.026 may be preferred between the first electrode 23 or 123, theinsulating layer 24 or 124, and the second electrode 25 or 125.Furthermore, for the second electrode 25 or 125, an expanded conductivearea as illustrated in the left figure of FIG. 6C for increased contactmay be preferable since this allows broader cutting or coagulation. Anouter tubular member 20 or 120 such as disclosed in the above figuresmay be preferably suitable to have an outer diameter of about 4 mm for amicrodebrider or shaver.

FIG. 7A, FIG. 7B, FIG. 7C, FIG. 8A, and FIG. 8B are further detailedillustrations of an outer tubular member 20′ or 120′ as identically orsimilarly described with respect to FIG. 2C, FIG. 2D, and FIG. 4B. Moreparticularly, FIG. 7A is a top view of an outer tubular member 20′ or120′. FIG. 7B is a side view of an outer tubular member 20′ or 120′.FIG. 7C is a bottom view of an outer tubular member 20′ or 120′. FIG. 8Ais an expanded end view of the tip portion of the outer tubular member20′ or 120′. FIG. 8B is an expanded bottom view of the tip portion ofthe outer tubular member 20′ or 120′ of FIG. 7C. FIG. 7A, FIG. 7B, FIG.7C, FIG. 8A, and FIG. 8B show some preferable relative ratios of firstelectrode 23′ or 123′, insulating zone 24′ or 124′, and the secondelectrode 25′ or 125′ even though other ratios are also contemplated. Anouter tubular member 20′ or 120′ such as disclosed in the above figuresmay be preferably suitable to have an outer diameter of about 2 mm for amicrodebrider or shaver. Even though FIG. 7B shows an example of runner25′a disposed on the side of the outer tubular member for thisasymmetrical bipolar electrode configuration, it should be understoodthat the runner 25′a may be disposed along the longitudinal axis in amanner that it equally or substantially equally bisects the open window21′ of the outer tubular member. It is contemplated that doing so willallow an operator to better determine the orientation of the openwindow, and it may also help the operator to determine how far theoperator may insert the tubular member into a surgical area such as fora turbinate surgical operation based on an insertion situation of therunner 25′a. Put it another way, the runner 25′a may be additionallyused as a marking tool for an operator to align the open window and/orinsertion estimation during an operation. In an embodiment, the runner25′a may be preferably disposed equally or substantially equallybisecting the open window for an outer tubular member with about 2 mmouter diameter.

In the above embodiments, the outer tubular member has a distal portionand a proximal portion. the proximal portion is configured to be fixedlyor detachably connectable to the handpiece, and the distal portion isconfigured to have an open window. The open window of the outer tubularmember is configured to admit or receive tissue to be cut for a surgicaloperation such as a nasal operation. The cut tissue fragments are thendrawn through the lumen of the inner tubular member by suction appliedat a suction connector. In the above embodiments, the outer tubularmember may be configured to be stationary. The inner tubular member maybe preferably configured to be open or to have an open window at itsdistal end. The inner tubular member may be configured to have acircular sharpened edge or a beveled sharpened edge or other suitablesharp edges such as serrated or knife type of edges if it has an opendistal end. It may be configured to have a type of toothed or serratedsharp edges if it is configured to have an open window disposed alongits distal end. It should be understood that the outer tubular membermay be configured to have more than one window at its distal end. Itshould also be understood that a bit larger open window may helpadmitting more tissue for cutting while a smaller window may facilitatea better suction. Accordingly, the open window of the outer tubularmember may be sized/shaped/configured/dimensioned in accordance with theneeds and/or functions of the medical device even though the open windowis preferably configured to be symmetrical or substantially symmetricalalong the longitudinal axis of the outer tubular member.

In the above embodiments, the inner tubular member has a distal portionand a proximal portion. The proximal portion may be configured to beoperably connectable to a cannulated plunger or cannulated armature orcannulated shaft. The distal portion may be preferably configured tohave an open distal end if it is used in a reciprocating mode. The opendistal end may be configured to be any suitable sharp edge for cuttingpurpose. For example, it may be configured to be circular with sharpedge. It may be configured to have beveled sharp edge. The bevel anglemay be, for example, at 45° degree in relation to the longitudinal axis.The inner tubular member may be configured to be movable relative to theouter tubular member. The distal portion may be preferably configured tohave an open window at the distal end if it is used to be rotated oroscillated and/or translated. The open window may be preferablyconfigured to be symmetrical or substantially symmetrical along thelongitudinal axis. The open window may be configured to have toothedtype of edge or other suitable sharp edge. The inner tubular member ispreferably configured to be flexible. In the above embodiments, the opendistal end of the inner tubular member and the open window of the outertubular member are configured to form a cutting tool or device during anoperation of the device.

In the above embodiments wherein the open window of the outer tubularmember is intended to be used as part of a cutting tool of the medicaldevice, the open window of the outer tubular member may be configured tohave an outer surface edge and an inner surface edge. The outer surfaceedge may be preferably configured to be smooth in order for it not tocause damage or harm to the tissue/passage way when the device is in theprocess of being inserted. The inner surface edge, in particular towardsthe distal end, may be preferably configured to be sharp so that thesharp edge may form a more efficient cutting tool with the sharp edge ofthe open distal end of the inner tubular member. Similarly, the opendistal end of the inner tubular member may be configured to have anouter surface edge and an inner surface edge. The outer surface edge maybe preferably configured to be sharp in order for it to form a moreefficient cutting tool with the inner surface edge of the outer tubularmember.

In the above embodiments wherein the open window of the outer tubularmember is intended to be used primarily as admitting tissue to be cut,the open window of the outer tubular member may be configured to havesmooth edges while the inner tubular member is then configured to havean open window. In such embodiments, the inner tubular member isconfigured to be rotatory/oscillatory and/or translational within theouter tubular member. The open window of the inner tubular member isconfigured to have toothed edges or other sharp edges capable of cuttingtissue while being rotated or oscillated. It should be understood thatother shapes or configurations are also contemplated for the open windowof the inner tubular member.

In the above embodiments, the tubular section may also be configured tocomprise more than two tubular members such as an inner tubular member,an outer tubular member and an intermediary tubular member. In suchembodiments, either the inner tubular member or the intermediary tubularmember may be configured to be operably connectable to the cannulatedshaft of the medical device. The inner tubular member or theintermediary tubular member may also be configured to be operablyconnectable to a motor. In such embodiments, the intermediary tubularmember may be configured to have an open window at its distal end. Insuch embodiments, the outer tubular member may be configured tocompletely cover the open window area of the intermediary tubular memberfor safe insertion of the medical device.

In all the above embodiments, it should be understood that theconnections, the sealing, and securing between the outer tubular member,the inner tubular member, the cannulated armature, the cannulatedplunger, the cannulated shaft, and the motor assembly may be achievedthrough the necessary supporting bearings, connectors, couplers,springs, and other means known in the art. It should also be understoodthat the connections, the sealing, and securing between other componentssuch as nosecone may be similarly achieved.

In another aspect, the present disclosure provides a method of making amedical device as described herein. In an embodiment, the methodincludes making a medical device with a first electrode disposed at thedistal end of the tubular member as described herein. In an embodiment,the present disclosure also provides a method of making a medical devicewith a first electrode and a second electrode disposed at the distal endof the tubular member as described herein. In an embodiment, the methodincludes making a medical device as described herein by using amicrofabrication process. In an embodiment, the method includes making amedical device as described herein by employing a flexible circuitprocess. In an embodiment, the method includes making a medical deviceas described herein by employing a conductive ink process.

In the above embodiments, the first electrode and the second electrodeare configured to provide RF energy to perform cutting and/orcoagulation for a medical device as described herein. The firstelectrode may be formed by insulating part of the distal end of ametallic outer tubular member such as stainless steel outer tubularmember while the second electrode may be made on a dielectric insulationlayer through microfabrication process, or flexible circuit process, orconductive ink process. For example, the dielectric insulation layer maybe deposited on a metallic tubular member through physical vapordeposition, or spray coating or injection molding, or heat shrinking, ordip coating or powder coating. Then, a conductive layer may be appliedto the dielectric insulation layer through physical vapor deposition orconductive inking. Finally, another optional insulation layer may beapplied to the conductive layer through a process similar to thatdescribed for the formation of the dielectric insulation layer such asphysical vapor deposition, or spray coating or injection molding, orheat shrinking, or dip coating or powder coating. The dielectricmaterials may be any suitable materials such as Si02, Al203, parylene,ceramic, liquid silicone rubber, nylon, polydimethylsiloxane (PDMS),polyimide, polyamide, polyester and other polymeric materials. Theconductive materials may be aluminum, stainless steel, silver, gold,titanium, copper, and solder. The additional insulation layer may bematerials such as SiO2, Al2O3, parylene, ceramic, liquid siliconerubber, nylon, polydimethylsiloxane, Halas and Epoxy. The dielectricinsulation layer or the additional insulation layer may be at athickness of from about 0.001″ to about 0.01″, preferably, from about0.001″ to about The conductive layer may be at a thickness of about0.001″ to about 0.01″, preferably, from about 0.001″ to about 0.002″.The preferred conductive material may be gold.

In the above embodiments when the electrical function of the firstelectrode is from the metallic outer tubular member and the electricalfunction of the second electrode is from the conductive layer disposedon an insulation layer, the open window and its neighbouring areas atthe distal end of the outer tubular member is kept intact to be used asthe first electrode. A dielectric layer is then placed around the outersurface of the outer tubular member. The second electrode issubsequently formed by placing a conductive layer over a dielectriclayer. This conductive layer is configured to have a runner which isconfigured to be connectable to a metallic wire. It should be understoodthat it is preferable to have similar overall cross-sectional areas foreach of the two electrodes because this helps ensure proper currentdensity across tissues. It should also be understood that it may bepreferable to maintain a consistent insulation gap between theelectrodes. For example, this gap may be optimized at approximatelybecause this distance allows for proper tissue effect when a propergenerator setting is used. It should further be understood that placingthe electrodes as close to the cutting window has advantages for asurgeon because it allows the surgeon to control bleeding without havingto re-orient the device.

In some embodiments, both the first electrode and the second electrodemay be formed from conductive layers disposed on a polymeric outertubular member through a method such as disclosed in the U.S. Pat. No.9,289,141, the contents of which are incorporated herein in its entiretyby reference. More particularly, both the first electrode and the secondelectrode may be made to have a head portion and a tail portion orrunner. The runner may be preferably run along the longitudinaldirection. The head portion of the first of the two electrodes may beconfigured to cover the open window and its neighboring areas of theouter tubular member. The head portion of the other electrode may thenbe configured to surround the first electrode to the extent that it doesnot interfere with the runner of the first electrode. The gap betweenthe two head portions is preferably configured to remain constant, forexample, at about 0.02″ to 0.030″. The head portion is the majorconductive area while the runner is a narrower portion that is used toextend between the electrode head and the point where the runnerterminates and is attached to a bundle of sheath of external wires. Eventhough a runner may be disposed in any manner, it is preferably disposedon the outer surface of the outer tubular member along its longitudinalaxis direction. In the above embodiments, there is no need for anadditional insulation layer between the first electrode and the secondelectrode since the outer tubular member itself is made ofnon-conductive polymeric material. Both of the conductive layers may bemade through a method as described herein and in the U.S. Pat. No.9,289,141.

In the above embodiments, the medical device may be configured for useas a microdebrider or shaver in the removal of nasal polyps, sub-mucosaldebulk of turbinate, and functional endoscopic sinus surgery (FESS),primarily in the office environment and/ or cost-sensitive regions. Itmay be a disposable debrider or shaver. In the above embodiments, themedical device may provide several benefits such as more precisecutting, lower blood loss or less bleeding in comparison with aconventional medical device without a bipolar design as described herein

In another embodiment, the present disclosure also provides a method ofcutting tissue. In an embodiment, the method includes providing amedical device having an inner tubular member and an outer tubularmember. In an embodiment, the method includes inserting the medicaldevice into a treatment site and positioning the medical deviceproperly. In an embodiment, the method includes turning on the device tocut tissue. More particularly, the method includes cutting tissue byreciprocating or oscillating and/or translating the inner tubular memberin relation to the outer tubular member wherein the outer tubular memberand the inner tubular member work to admit and cut tissue. It should beunderstood that once the medical device is turned on, the open window ofthe outer tubular member constantly aligns with the open distal end ofthe inner tubular member to capture/admit and cut the tissue. It shouldalso be understood that once the device is powered off, the distal endof the inner tubular member and the distal end of the outer tubularmember may be configured to form a closed configuration to keep thedevice safe for the patient. In an embodiment, the present disclosurealso provides a method of cutting tissue and coagulating following thecutting.

It is understood that the above description is intended to beillustrative and not restrictive. Many embodiments as well as manyapplications besides the examples provided will be apparent to those ofskill in the art upon reading the above description. The scope of theteachings should, therefore, be determined not with reference to theabove description, but should instead be determined with reference tothe appended claims, along with the full scope of equivalents to whichsuch claims are entitled. The disclosures of all articles andreferences, including patent applications and publications, areincorporated by reference for all purposes. The omission in thefollowing claims of any aspect of subject matter that is disclosedherein is not a disclaimer of such subject matter, nor should it beregarded that the inventors did not consider such subject matter to bepart of the disclosed inventive subject matter.

The principles of the present disclosure may be better understood withreference to the drawings and the accompanying descriptions, whereinlike reference numerals have been used throughout to designate identicalor similar elements. It should be understood that these drawings are notnecessarily are drawn to scale. They are presented just for illustrativepurposes only, and are not intended to limit the scope of thedisclosure. Examples of materials, dimensions, and constructions areincluded for some elements. Those of ordinary skill in the art shouldunderstand that many of the examples provided have suitable alternativesand these alternatives should also be considered within the scope ofthis disclosure. Moreover, certain terminology is used herein forconvenience only and is not to be taken as a limitation on the presentdisclosure.

The explanations and illustrations presented herein are intended toacquaint others skilled in the art with the disclosure, its principles,and its practical applications. Those skilled in the art may adapt andapply the disclosure in numerous forms, as may be best suited to therequirements of a particular use. The specific embodiments of thepresent disclosure as set forth are not intended to be exhaustive orlimiting of the invention. The scope of the invention should bedetermined not with reference to the above description, but should bedetermined with reference to the appended claims, along with the fullscope of equivalents to which such claims are entitled.

The terms “one embodiment”, “an embodiment”, “another embodiment”, “someembodiments”, “other embodiments”, “above embodiment”, and similarexpressions indicate that the embodiment or embodiments described mayinclude a particular feature, structure, or characteristic, but everyembodiment may not necessarily include the particular feature,structure, or characteristic. Moreover, such phrases are not necessarilyreferring to the same embodiment. Furthermore, when a particularfeature, structure, or characteristic is described in connection with anembodiment, it would be within the knowledge of one skilled in the artto incorporate such feature, structure, or characteristic into otherembodiments, whether or not explicitly described, unless clearly statedto the contrary. That is, the various individual elements describedbelow, even if not explicitly shown in a particular combination, arenevertheless contemplated as being combinable with each other to formother additional embodiments or to complement and/or enrich thedescribed embodiment or embodiments, as would be understood by one ofordinary skill in the art.

The articles “a”, “an” and “the” are used herein to refer to one or tomore than one (i.e. to at least one) of the grammatical object of thearticle unless otherwise clearly indicated by contrast. By way ofexample, “an element” means one element or more than one element.

The term “including” is used herein to mean, and is used interchangeablywith, the phrase “including but notlimited to”. The term “or” is usedherein to mean, and is used interchangeably with, the term “and/or”,unless context clearly indicates otherwise.

The term “such as” is used herein to mean, and is used interchangeably,with the phrase “such as but not limited to”. Unless specifically statedor obvious from context, as used herein, the term “about” is understoodas within a range of normal acceptance in the art, for example withinstandard deviations of the mean.

The term “proximal” is herein used to mean a position or directionclosest to a user of the device and is in a position or directionopposite to the term “distal”.

The term “distal” is herein used to mean a position or directionfurthest away from a user of the device and is a position or directionopposite to the term “proximal”.

The term “cannulated” used throughout the specification refers to ageneral ‘tube’ or ‘tubular’, or ‘hollowed out cylindrical’ shape, or anygeneral cylinder shape having an outside diameter and an insidediameter, for example.

All numeric values are herein assumed to be modified by the term “about”whether or not explicitly indicated. The term “about”, in the context ofnumeric values, generally refers to a range of numbers that one of skillin the art would consider equivalent to the recited value (i.e., havingthe same function or result). In many instances, the term “about” mayinclude numbers that are rounded to the nearest significant figure.Other uses of the term “about” (i.e., in a context other than numericvalues) may be assumed to have their ordinary and customarydefinition(s), as understood from and consistent with the context of thespecification, unless otherwise specified. Even more specifically,“about” can be understood as within 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%,1%, 0.5%, 0.1%, 0.05%, or 0.01% of the stated value.

Unless otherwise stated, all ranges include both endpoints and allnumbers between the endpoints. The use of “about” or “approximately” inconnection with a range applies to both ends of the range. Thus, “about10 to 30” is intended to cover “about 10 to about 30”, inclusive of atleast the specified endpoints.

1. (canceled)
 2. A medical device comprising: a tubular member extendingalong a longitudinal axis from a proximal end to a distal end, a topside of the tubular member including an open window disposed at thedistal end; a first electrode disposed at the distal end of the tubularmember and surrounding the open window of the tubular member or itsneighboring region; an insulation zone surrounding the first electrode;and a second electrode surrounding the insulation zone, the secondelectrode including an expanded head portion on a bottom side of thetubular member.
 3. The medical device of claim 2, wherein the secondelectrode further includes a runner that extends proximally on an outersurface of the tubular member.
 4. The medical device of claim 3, whereinthe runner extends toward the proximal end of the tubular member in adirection substantially parallel to the longitudinal axis.
 5. Themedical device of claim 4, wherein the head portion bifurcates from therunner at a location proximal to the open window.
 6. The medical deviceof claim 2, wherein the open window of the tubular member issubstantially symmetrical along the longitudinal axis of the tubularmember.
 7. The medical device of claim 2, wherein the first electrode issubstantially symmetrical along the longitudinal axis of the tubularmember.
 8. The medical device of claim 2, wherein the second electrodeis substantially symmetrical along the longitudinal axis of the tubularmember.
 9. The medical device of claim 2, wherein the insulation zone issubstantially symmetrical along the longitudinal axis of the tubularmember.
 10. The medical device of claim 2, further comprising an innertubular member configured to be received within the tubular member. 11.The medical device of claim 10, wherein the inner tubular member has anopen distal end.
 12. The medical device of claim 11, wherein the opendistal end of the inner tubular member and the open window of thetubular member are configured to form a cutting tool during an operationof the medical device.
 13. The medical device of claim 10, wherein theinner tubular member has a distal end and an open window disposed at thedistal end.
 14. A medical device comprising: a tubular member extendingalong a longitudinal axis from an open proximal end to a closed distalend, the tubular member including an open window disposed at the distalend; a first electrode surrounding the open window of the tubular memberor its neighboring region; an insulation zone surrounding the firstelectrode; and a second electrode surrounding the insulation zone, thesecond electrode including an expanded conductive area on a side of thetubular member opposite to the open window.
 15. The medical device ofclaim 14, wherein the second electrode is disposed on a dielectriclayer.
 16. The medical device of claim 14, wherein both the firstelectrode and the second electrode are substantially symmetrical alongthe longitudinal axis of the tubular member.
 17. The medical device ofclaim 14, wherein both the first electrode and the second electrode areasymmetrical along the longitudinal axis of the tubular member.
 18. Themedical device of claim 14, further comprising an inner tubular memberconfigured to be received within the tubular member.
 19. A medicaldevice comprising: an outer tubular member extending along alongitudinal axis from a proximal end to a distal end, the outer tubularmember including an open window disposed at the distal end; an innertubular member configured to be received within the outer tubularmember; a first electrode disposed at the distal end of the outertubular member and surrounding the open window of the outer tubularmember or its neighboring region; an insulation zone surrounding thefirst electrode; and a second electrode surrounding the insulation zone;wherein the second electrode surrounds the insulation zone by connectingbifurcated segments of the second electrode at a location proximal tothe open window.
 20. The medical device of claim 19, wherein the secondelectrode is disposed on a dielectric layer.
 21. The medical device ofclaim 19, wherein the second electrode includes an expanded conductivearea.